@webex/common/test/unit/spec/capped-debounce.js

Common utilities for Cisco Webex

/*!
 * Copyright (c) 2015-2020 Cisco Systems, Inc. See LICENSE file.
 */

import {assert} from '@webex/test-helper-chai';
import sinon from 'sinon';
import {cappedDebounce} from '@webex/common';
import FakeTimers from '@sinonjs/fake-timers';

describe('common', () => {
  describe('cappedDebounce()', () => {
    let clock;

    beforeEach(() => {
      clock = FakeTimers.install({now: Date.now()});
    });

    afterEach(() => {
      clock.uninstall();
    });

    it('requires a function', () => {
      assert.throws(cappedDebounce, /`fn` must be a function/);
    });

    it('requires a `wait`', () => {
      assert.throws(cappedDebounce.bind(null, sinon.spy()), /`wait` is required/);
    });

    it('requires a `maxWait`', () => {
      assert.throws(cappedDebounce.bind(null, sinon.spy(), 5), /`options.maxWait` is required/);
    });

    it('requires a `maxCalls`', () => {
      assert.throws(
        cappedDebounce.bind(null, sinon.spy(), 5, {maxWait: 10}),
        /`options.maxCalls` is required/
      );
    });

    it('returns a function that will execute once it stops being invoked for `wait` ms', () => {
      const spy = sinon.spy();
      const fn = cappedDebounce(spy, 50, {maxWait: 1000, maxCalls: 10000});

      fn();
      fn();
      fn();
      fn();
      assert.notCalled(spy);
      clock.tick(20);
      assert.notCalled(spy);
      clock.tick(40);
      assert.calledOnce(spy);
      clock.tick(40);
      assert.calledOnce(spy);
    });

    it('returns a function that will execute once if it continues to be invoked for `wait` ms after `maxWait` ms', () => {
      const spy = sinon.spy();
      const fn = cappedDebounce(spy, 100, {maxWait: 130, maxCalls: 10000});

      fn();
      assert.notCalled(spy);
      clock.tick(50);
      fn();
      assert.notCalled(spy);
      clock.tick(50);
      fn();
      assert.notCalled(spy);
      clock.tick(50);
      fn();
      assert.calledOnce(spy);
    });

    it('returns a function that will execute once it has been invoked `maxCalls` times', () => {
      const spy = sinon.spy();
      const fn = cappedDebounce(spy, 50, {maxWait: 100, maxCalls: 4});

      fn();
      assert.notCalled(spy);
      fn();
      assert.notCalled(spy);
      fn();
      assert.notCalled(spy);
      fn();
      assert.called(spy);
    });

    it('returns a function that will execute once it has been invoked `maxCalls` times and executes again after `maxWait` ms', () => {
      const spy = sinon.spy();
      const fn = cappedDebounce(spy, 50, {maxWait: 100, maxCalls: 3});

      fn();
      fn();
      fn();
      assert.called(spy);
      fn();
      fn();
      clock.tick(150);
      assert.calledTwice(spy);
    });
  });
});